IO2 PEARLS AND PEARLING 



cake of laundry soap is tied to a weight on the end of a 

 line and dragged a few feet on the bed of the river. If 

 the soap gathers sand it is a proof that the river bed is 

 sandy at that place. 



When small shells are found open upon the bank of 

 rivers or lakes it is an indication that there are shells in 

 the water. Muskrats, raccoons and other predacious ani- 

 mals bring out the small mussels for food. 



The distorted shells known as "cripples" are the ones 

 which generally contain the fine pearls, yet only certain 

 ones of these contain pearls. They are described fully 

 in another chapter. 



The appearance of the shores often indicate the amount 

 of labor that will be involved in pearl hunting in a cer- 

 tain locality. 



A large number of old trees, logs and brush in the 

 water along the shores, indicate a great many snags, or 

 "hang ups," on the bottom of the river, which will cause 

 unlimited trouble when the crow-foot dredge or dip net 

 is used. The logs and stumps have been especially trou- 

 blesome in the Illinois River. 



The parasites should receive special consideration in 

 prospecting for pearls. These are the causes of the for- 

 mation of most pearls, baroques and slugs, so it is very 

 important to select a pearl fishery where these are most 

 abundant. Among the parasites that are found in the 

 mussels there are several that are especially prominent. 

 The Cotyldspis insignis, Leidy, can be seen with the naked 

 eye and some of them resemble a small pale leech. An- 



